Use Fortytwo with the AI SDK

The AI SDK is a TypeScript toolkit for building AI apps and agents. It reaches the Fortytwo API through its OpenAI-compatible provider, @ai-sdk/openai-compatible.

Before you start: create a Fortytwo API key and buy credits — see Quickstart, step 1. Keep the key on your server: the API cannot be called from a web page in the browser.

Setting	Value
Base URL	`https://api.fortytwo.network/v1`
Model ID	`qwen/qwen3.8-27b` in this guide, or another ID from Models

Install

npm install ai @ai-sdk/openai-compatible zod

pnpm add ai @ai-sdk/openai-compatible zod

yarn add ai @ai-sdk/openai-compatible zod

bun add ai @ai-sdk/openai-compatible zod

zod is needed only for tools and structured output. Put your key in an environment variable:

export FORTYTWO_API_KEY="<your Fortytwo key>"

Create the provider

fortytwo.ts

import { createOpenAICompatible } from "@ai-sdk/openai-compatible";

export const fortytwo = createOpenAICompatible({
  name: "fortytwo",
  baseURL: "https://api.fortytwo.network/v1",
  apiKey: process.env.FORTYTWO_API_KEY,
  includeUsage: true,
  supportsStructuredOutputs: true,
});

export const model = fortytwo("qwen/qwen3.8-27b");

includeUsage adds token counts to streamed responses.
supportsStructuredOutputs sends JSON schemas in strict mode, which the Fortytwo API supports.
fortytwo("qwen/qwen3.8-27b") takes any model ID from Models.

Generate text

import { generateText } from "ai";
import { model } from "./fortytwo";

const { text, reasoningText, usage } = await generateText({
  model,
  prompt: "Explain prompt caching in two sentences.",
  providerOptions: { fortytwo: { reasoningEffort: "medium" } },
});

reasoningText holds the model’s reasoning. reasoningEffort is sent as reasoning_effort; the accepted values and the default are in Models.

Stream

import { streamText } from "ai";
import { model } from "./fortytwo";

const result = streamText({
  model,
  prompt: "Write a haiku about distributed inference.",
});

for await (const chunk of result.textStream) {
  process.stdout.write(chunk);
}

Call tools

import { generateText, stepCountIs, tool } from "ai";
import { z } from "zod";
import { model } from "./fortytwo";

const { text } = await generateText({
  model,
  prompt: "What is the weather in London?",
  tools: {
    weather: tool({
      description: "Get the current weather for a city",
      inputSchema: z.object({ city: z.string() }),
      execute: async ({ city }) => ({ city, temperatureC: 12 }),
    }),
  },
  stopWhen: stepCountIs(5),
});

stopWhen lets the model call a tool, read the result and answer in the same call.

Get structured output

import { generateText, Output } from "ai";
import { z } from "zod";
import { model } from "./fortytwo";

const { output } = await generateText({
  model,
  prompt: "Give me a vegetarian lasagne recipe.",
  output: Output.object({
    schema: z.object({
      name: z.string(),
      ingredients: z.array(z.string()),
      steps: z.array(z.string()),
    }),
  }),
});

Send an image

import { readFileSync } from "node:fs";
import { generateText } from "ai";
import { model } from "./fortytwo";

const { text } = await generateText({
  model,
  messages: [
    {
      role: "user",
      content: [
        { type: "text", text: "What is on this screenshot?" },
        { type: "file", data: readFileSync("screenshot.png"), mediaType: "image/png" },
      ],
    },
  ],
});

Supported formats and limits are in Images.

Limits

Chat Completions only: the AI SDK’s OpenAI Responses provider (@ai-sdk/openai with openai.responses(...)) does not work with the Fortytwo API. Use @ai-sdk/openai-compatible as above.
Requests go out with the AI SDK’s own User-Agent; add a headers setting to createOpenAICompatible if you want to tag your traffic.

More options: OpenAI-compatible providers .

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